The Extremely Luminous Quasar Survey in the SDSS Footprint. I. Infrared-based Candidate Selection
Studies of the most luminous quasars at high redshift directly probe the evolution of the most massive black holes in the early universe and their connection to massive galaxy formation. However, extremely luminous quasars at high redshift are very rare objects. Only wide-area surveys have a chance...
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ndltd-arizona.edu-oai-arizona.openrepository.com-10150-6271032018-03-25T03:00:28Z The Extremely Luminous Quasar Survey in the SDSS Footprint. I. Infrared-based Candidate Selection Schindler, Jan-Torge Fan, Xiaohui McGreer, Ian D. Yang, Qian Wu, Jin Jiang, Linhua Green, Richard Univ Arizona, Steward Observ galaxies: nuclei quasars: general Studies of the most luminous quasars at high redshift directly probe the evolution of the most massive black holes in the early universe and their connection to massive galaxy formation. However, extremely luminous quasars at high redshift are very rare objects. Only wide-area surveys have a chance to constrain their population. The Sloan Digital Sky Survey (SDSS) has so far provided the most widely adopted measurements of the quasar luminosity function at z > 3. However, a careful re-examination of the SDSS quasar sample revealed that the SDSS quasar selection is in fact missing a significant fraction of z greater than or similar to 3 quasars at the brightest end. We identified the purely optical-color selection of SDSS, where quasars at these redshifts are strongly contaminated by late-type dwarfs, and the spectroscopic incompleteness of the SDSS footprint as the main reasons. Therefore, we designed the Extremely Luminous Quasar Survey (ELQS), based on a novel near-infrared JKW2 color cut using Wide-field Infrared Survey Explorer mission (WISE) AllWISE and 2MASS all-sky photometry, to yield high completeness for very bright (m(i) < 18.0) quasars in the redshift range of 3.0 <= z <= 5.0. It effectively uses random forest machinelearning algorithms on SDSS and WISE photometry for quasar-star classification and photometric redshift estimation. The ELQS will spectroscopically follow-up similar to 230 new quasar candidates in an area of similar to 12,000 deg(2) in the SDSS footprint to obtain a well-defined and complete quasar sample for an accurate measurement of the brightend quasar luminosity function (QLF) at 3.0 <= z <= 5.0. In this paper, we present the quasar selection algorithm and the quasar candidate catalog. 2017-12-06 Article The Extremely Luminous Quasar Survey in the SDSS Footprint. I. Infrared-based Candidate Selection 2017, 851 (1):13 The Astrophysical Journal 1538-4357 10.3847/1538-4357/aa9929 http://hdl.handle.net/10150/627103 http://arizona.openrepository.com/arizona/handle/10150/627103 The Astrophysical Journal en http://stacks.iop.org/0004-637X/851/i=1/a=13?key=crossref.0fe564d8e606e49c374ae6d28e61ec02 © 2017. The American Astronomical Society. All rights reserved. IOP PUBLISHING LTD |
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galaxies: nuclei quasars: general |
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galaxies: nuclei quasars: general Schindler, Jan-Torge Fan, Xiaohui McGreer, Ian D. Yang, Qian Wu, Jin Jiang, Linhua Green, Richard The Extremely Luminous Quasar Survey in the SDSS Footprint. I. Infrared-based Candidate Selection |
description |
Studies of the most luminous quasars at high redshift directly probe the evolution of the most massive black holes in the early universe and their connection to massive galaxy formation. However, extremely luminous quasars at high redshift are very rare objects. Only wide-area surveys have a chance to constrain their population. The Sloan Digital Sky Survey (SDSS) has so far provided the most widely adopted measurements of the quasar luminosity function at z > 3. However, a careful re-examination of the SDSS quasar sample revealed that the SDSS quasar selection is in fact missing a significant fraction of z greater than or similar to 3 quasars at the brightest end. We identified the purely optical-color selection of SDSS, where quasars at these redshifts are strongly contaminated by late-type dwarfs, and the spectroscopic incompleteness of the SDSS footprint as the main reasons. Therefore, we designed the Extremely Luminous Quasar Survey (ELQS), based on a novel near-infrared JKW2 color cut using Wide-field Infrared Survey Explorer mission (WISE) AllWISE and 2MASS all-sky photometry, to yield high completeness for very bright (m(i) < 18.0) quasars in the redshift range of 3.0 <= z <= 5.0. It effectively uses random forest machinelearning algorithms on SDSS and WISE photometry for quasar-star classification and photometric redshift estimation. The ELQS will spectroscopically follow-up similar to 230 new quasar candidates in an area of similar to 12,000 deg(2) in the SDSS footprint to obtain a well-defined and complete quasar sample for an accurate measurement of the brightend quasar luminosity function (QLF) at 3.0 <= z <= 5.0. In this paper, we present the quasar selection algorithm and the quasar candidate catalog. |
author2 |
Univ Arizona, Steward Observ |
author_facet |
Univ Arizona, Steward Observ Schindler, Jan-Torge Fan, Xiaohui McGreer, Ian D. Yang, Qian Wu, Jin Jiang, Linhua Green, Richard |
author |
Schindler, Jan-Torge Fan, Xiaohui McGreer, Ian D. Yang, Qian Wu, Jin Jiang, Linhua Green, Richard |
author_sort |
Schindler, Jan-Torge |
title |
The Extremely Luminous Quasar Survey in the SDSS Footprint. I. Infrared-based Candidate Selection |
title_short |
The Extremely Luminous Quasar Survey in the SDSS Footprint. I. Infrared-based Candidate Selection |
title_full |
The Extremely Luminous Quasar Survey in the SDSS Footprint. I. Infrared-based Candidate Selection |
title_fullStr |
The Extremely Luminous Quasar Survey in the SDSS Footprint. I. Infrared-based Candidate Selection |
title_full_unstemmed |
The Extremely Luminous Quasar Survey in the SDSS Footprint. I. Infrared-based Candidate Selection |
title_sort |
extremely luminous quasar survey in the sdss footprint. i. infrared-based candidate selection |
publisher |
IOP PUBLISHING LTD |
publishDate |
2017 |
url |
http://hdl.handle.net/10150/627103 http://arizona.openrepository.com/arizona/handle/10150/627103 |
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